Tongs are a common tool used for grasping items manually, for example, where items are hot or inaccessible. Kitchen tongs are commonly used which include two elongate tong members pivotally joined together with a hinge pin. Various spring configurations are used in the prior art to bias the tong members to a normally open position, and various mechanical latches are used to hold the tongs in a closed position. The user exerts pressure manually by grasping the tong members forward of the hinge pin squeezing against the biasing force of the spring to close the tongs and releasing the grip to permit the tongs to open.
A number of challenges confront the manufacturers of such tongs, especially for kitchen use. Low cost, durability, simplicity and ease of cleaning are paramount. The spring mechanism and any latch mechanism to lock the tongs in a closed position must be of a very simple construction. Tongs are generally very inexpensive items and minimal labour and materials in manufacturing tongs is the goal of manufacturers. Complex locking or spring loading mechanisms are highly undesirable since they often provide crevices or ridges within which food and accompanying bacteria may accumulate resulting in a health hazard. Simple open structures are preferred to permit adequate cleaning and disinfecting with conventional dishwashing equipment.
Rugged durable construction is also highly desirable since components that break or fall apart may unintentionally fall into the food being prepared. In addition, it is highly desirable to have tongs which can be operated with one hand to simplify repeated use by professional or amateur cooks. Professional cooks work at a rapid pace and demand tools that are simple to use, and can be operated single-handed. Tongs that require too much attention to operate or that cannot stand up under rough treatment will be quickly discarded by a professional cook.
Many of the conventional tongs available include a separate locking device which must be operated with both hands by the user. A significant disadvantage of many prior art locking devices is that the locking device engages unexpectedly during use and locks the tongs in a closed position when that result was not intended by the user.
Examples of the prior art include U.S. Pat. No. 5,199,756 to Bartlett et al. Bartlett provides a conventional pair of tong members hinged at a pivot pin with a bow spring wrapped about the pivot pin biasing the tong members to an open position. A generally rectangular slotted tab is provided as a locking mechanism slidably disposed with the slot engaging the pivot pin. The outer rectangular edges of the tab engage and disengage a rearward portion of the tong members applying a levering or wedging force to close the tong members against the biasing pressure of the bow spring.
A disadvantage of this Bartlett device is that a separate locking device is required which increases manufacturing costs and provides additional areas within which food and bacteria accumulate. The sliding plate serves to lock the tongs in a closed position but also increases the cost of manufacturing and assembly while providing additional hidden areas within which food and bacteria can accumulate.
A second example is provided in U.S. Pat. No. 2,864,645 to Meldrum, which provides a similar pair of tong members hinged together at a pivot pin. A locking device is provided in the form of a sliding bolt which rides in a slotted channel in the tong members and interlocks with a locking dog adjacent to the pivot pin. Disadvantages of this system are the risk of unintentional locking during normal use, unnecessarily complex manufacturing of additional components required for the locking mechanism and the presence of crevices or ridges within which food or bacteria can accumulate.
U.S. Pat. Nos. 2,768,856 to Wright and 2,532,406 to Jernigan and design Pat. No. 165,869 to Reiner, all include a locking mechanism comprising a sliding ring that slides on the outside of the hinged tong members to lock them in a closed position. The external ring used as a locking device,however, has an aggravating tendency when the user squeezes the tong members together to close about an item to be grasped, to engage the sliding ring on the outside of the tong members unintentionally holding the tong members in a locked position. This is a especially annoying for professional cooks when used repeatedly and in circumstances where speed is essential. Invariably, the professional user will simply remove the locking outside ring to avoid aggravation.
Therefore, it is desirable to provide a set of tongs which is extremely simple and inexpensive to manufacture.
It is also desirable to provide a set of tongs which is easily cleaned with existing kitchen cleaning equipment.
It is also desirable to provide a set of tongs which can be operated with a single hand freeing the user from using both hands to engage and disengage the locking mechanism. It is also desirable to provide a locking mechanism for tongs which does not engage unintentionally and unexpectedly.